Bad tank purchase?

[WestCoastDivr]

At the beginning of my diving career (in my infinite wisdom because I obviously knew everything at that point ) I went ahead and purchased two new sherwood HP 100 steel cylinders planning to use them as doubles in the future. They are fairly new as they were created in mid 2012, but I have recently learned that many people stay away from the sherwood/asahi spun tanks which I was unaware of. They are 3442 psi rather than 3500 and 3/4" valves rather than the older 7/8" valves so I dodged at least some of the asahi bullet. I am also a cold water diver so the extra negative buoyancy may not make them unusable in doubles. A negative is that they are dot sp12079 tanks, however, meaning that the permit may not be renewed at some point in the future. I suppose the questions that I have are
1. what are the chances of the permit not being renewed/how often does a special permit get dropped?
2. can individuals apply to renew the permit or is only the company able to do that? (probably a stupid question)
3. Besides what I have listed, are there any other large negatives or things that I should be aware of?

Sorry about the relative n00bery of this post, I saw some older posts about the spun tanks but they were fairly old or didn't answer my questions. Any wisdom offered is greatly appreciated as I obviously still have a lot to learn

 

[TheRealScubaSteve]

Was just talking about those tanks a few days ago at the dive shop. Apparently, the steel they use in them is much more prevalent to rust quickly, particularly on the inside of the tanks and under the tank boots. I don't have any personal experience with them, but extra care in cleaning might be something to consider. A quick Google search for Asahi scuba tanks + rust brought up similar responses.

 

[eelnoraa]

If spec is HP103 @ 3500psi Bouyancy full -11.5 Bouyancy 500 psi -4.4

So not bad at all for single tank. This kind of negative buoyancy is good for cold water single tank diving. I would say just use them as single tank. Then when time come to dive double, you can decide later.

-4.4 is on the heavy side for double. It really depends on the kind of exposure suit you have. Not impossible.

 

[WestCoastDivr]

If spec is HP103 @ 3500psi Bouyancy full -11.5 Bouyancy 500 psi -4.4

So not bad at all for single tank. This kind of negative buoyancy is good for cold water single tank diving. I would say just use them as single tank. Then when time come to dive double, you can decide later.

-4.4 is on the heavy side for double. It really depends on the kind of exposure suit you have. Not impossible.

I dive a drysuit with fairly heavy undergarments because the water temp is usually between 42 and 48 degrees F. I don't understand how the extra 2ish pounds above a comparable worthington or faber hp 100 would be negative. In my mind it simply takes 4 pounds off a weight belt, right?

---------- Post added July 17th, 2014 at 12:39 AM ----------

Was just talking about those tanks a few days ago at the dive shop. Apparently, the steel they use in them is much more prevalent to rust quickly, particularly on the inside of the tanks and under the tank boots. I don't have any personal experience with them, but extra care in cleaning might be something to consider. A quick Google search for Asahi scuba tanks + rust brought up similar responses.

I'll take extra care cleaning the tank but I don't think there's anything I can do about the inside of the tanks

 

[Max Speed]

I believe the exemption has already been renewed through 2015. I believe Sherwood / Genesis will stay on top of renewals.

Some of these tanks had the Genesis or Scubadist.com markings ground off the crown of the tank before painting. Apparently they were possibly caught in the production chain after Scubadist.com went belly up. Those grind marks could be a visual or hydro inspection problem.

 

[WestCoastDivr]

I believe the exemption has already been renewed through 2015. I believe Sherwood / Genesis will stay on top of renewals.

Some of these tanks had the Genesis or Scubadist.com markings ground off the crown of the tank before painting. Apparently they were possibly caught in the production chain after Scubadist.com went belly up. Those grind marks could be a visual or hydro inspection problem.

The page that I read said they were renewed through 2017. However, I'm worried about further into the future because I almost certainly won't have the money for new tanks in the next 6ish years as I'll be paying for college

 

[kwinter]

Yes, anyone can apply for the exemption to be renewed. I wouldn't worry about that part.


iPhone. iTypo. iApologize.

 

[textilet]

I sold my set for a couple reasons:
The valves having an odd thread size meant the manifold choices were limited and the valves and manifold weren't interchangeable with the other sets of doubles I had. Also the extra negative buoyancy was an issue because with double Worthington and associated other gear I need basically no added weight. So there wasn't weight to take off the weight belt. I also remember them trimming out differently than my Worthington sets which is annoying if you just want to dial in a double 100 configuration. Having the Asahi set in the mix meant extra effort to incorporate oddball gear into a system based around Worthingtons- also all the same annoyances came up when I wanted to split the sets and use them as singles. If I only had the Asahi to use, much of this wouldn't apply.

 

[WestCoastDivr]

I sold my set for a couple reasons:
The valves having an odd thread size meant the manifold choices were limited and the valves and manifold weren't interchangeable with the other sets of doubles I had. Also the extra negative buoyancy was an issue because with double Worthington and associated other gear I need basically no added weight. So there wasn't weight to take off the weight belt. I also remember them trimming out differently than my Worthington sets which is annoying if you just want to dial in a double 100 configuration. Having the Asahi set in the mix meant extra effort to incorporate oddball gear into a system based around Worthingtons- also all the same annoyances came up when I wanted to split the sets and use them as singles. If I only had the Asahi to use, much of this wouldn't apply.

Well, like I said, I bought the newer models with the standard thread size of 3/4" so the problem of manifolds and valves not being interchangeable will not be an issue. I suppose the only way to tell if I'm going to be overweighted will be to try it but hoping the extra weight will simply offset my drysuit. Thanks for the input


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[rhwestfall]

with Worthington tanks OOP, folks may have to consider them as a more normal choice, despite their characteristics...